TWI452496B - Signal processing method of a touch panel - Google Patents

Description

Touch panel signal processing method

The invention relates to a signal processing method, in particular to a signal processing method for a touch panel.

Flat Panel Display (FPD) has been widely used in multimedia players, mobile phones, personal digital assistants (PDAs), computer monitors, or flat-panel TVs because of its slimness, power saving, and low radiation. And other electronic products. In addition, the function of performing touch input using a display device has become popular, that is, the application of the touch display device has become more and more widespread.

In general, the touch panel of the touch display device is mainly a resistive touch panel and a capacitive touch panel; the resistive touch panel is positioned with a voltage drop to touch the touch position, but cannot provide a multi-touch feeling. The measurement function, the capacitive touch panel is used to signal the change of the capacitance corresponding to the sensing capacitance of the touch point to locate the touch position.

Since the capacitive touch panel can provide multi-touch sensing function, it has become a technology adopted by many people. As can be seen from the above, a flat display device with a touch sensing mechanism generally includes a display panel and a capacitive touch panel attached thereto, wherein the capacitive touch panel can be detected according to the sensing determination array 100 shown in FIG. The basis for judging the touch event. As shown in FIG. 1 , the sensing determination array 100 is a 3×3 array including a first touch sensing unit SUc located at the center of the array, and a plurality of second touch sensing units SUa1 adjacent to the first touch sensing unit SUc. ~ SUa8. The first touch sensing unit SUc is for outputting the first sensing signal SSc, and the plurality of second touch sensing units SUa1 to SUa8 are respectively for outputting the second sensing signals SSa1 to SSa8. The processing method for the sensing determination array 100 is to first calculate an average value of the plurality of second sensing signals SSa1 to SSa8, and then add the average value to the preset first critical value to generate a second critical value, and then the first A sensing signal SSc is compared with a second threshold to determine whether a first touch sensing unit SUc has a touch event.

However, calculating the average value of the plurality of second sensing signals SSa1 to SSa8 may reduce the signal processing accuracy. In addition, when the display panel performs the screen writing operation, the high-voltage AC pixel signal will generate severe electric field noise and interfere with the sensing operation of the capacitive touch panel, resulting in the capacitive touch panel outputting the wrong sensing signal, especially when heavy occurs. When the touch event is pressed, the electric field interference in the area affected by the heavy press is particularly serious. At this time, the processing method is easily affected by the error sensing signal and the touch event is misjudged, thereby causing the action of the subsequent stage circuit. Values to avoid misjudgment touch events may not detect a light touch touch event.

Accordingly, it is an object of the present invention to provide a signal processing method for a touch panel that improves signal processing accuracy and thereby provides a highly reliable touch detection mechanism.

Therefore, in accordance with an embodiment of the present invention, a signal processing method is disclosed for operating a touch panel having a first touch sensing unit and a plurality of second touch sensing units adjacent to the first touch sensing unit. In the operation of the method, the first sensing signal of the first touch sensing unit is amplified by N times to generate a first signal, wherein N is the number of the plurality of second touch sensing units, and then the second second touch sensing The second sensing signals of the unit are added to generate a second signal, and the second signal is subtracted from the first signal to generate a difference signal, and then the difference signal is compared with the critical difference to generate a comparison result, and then the comparison result is obtained according to the comparison result. Determining whether the first touch sensing unit has a touch event.

In the following, the signal processing method of the touch panel according to the present invention is described in detail with reference to the accompanying drawings, but the embodiments are not intended to limit the scope of the present invention, and the method flow number is not To limit the order of execution, any process that is recombined by method steps, and methods that have equal power are all covered by the present invention.

FIG. 2 is a flow chart of the first embodiment of the signal processing method based on the sensing determination array 100 shown in FIG. 1 according to the present invention. As shown in FIG. 2, the process 200 of the signal processing method of the touch panel includes the following steps:

Step S205: The first sensing signal SSc of the first touch sensing unit SUc is captured, and the second sensing signal SSa1 of the plurality of second touch sensing units SUa1 to SUa8 adjacent to the first touch sensing unit SUc is captured. SSa8;

Step S209: comparing the first sensing signal SSc with the noise threshold to generate a first pre-comparison result;

Step S210: determining whether the first sensing signal SSc is not greater than the noise threshold according to the first pre-comparison result, if the first sensing signal SSc is not greater than the noise threshold, step S290 is performed, otherwise step S214 is performed;

Step S214: comparing the first sensing signal SSc with each of the second sensing signals SSa1 SSaa8 to generate a second pre-comparison result;

Step S215: determining, according to the second pre-comparison result, whether the first sensing signal SSc is not greater than any one of the plurality of second sensing signals SSa1 to SSa8, if the first sensing signal SSc is not greater than any of the plurality of second sensing signals SSa1 to SSa8. , step S290 is performed, otherwise step S220 is performed;

Step S220: The first sensing signal SSc is amplified by N times to generate a first signal, where N is the number of the plurality of second touch sensing units SUa1 to SUa8;

Step S225: adding a plurality of second sensing signals SSa1 to SSa8 to generate a second signal;

Step S230: Subtracting the second signal from the first signal to generate a difference signal;

Step S234: comparing the difference signal with the critical difference to generate a comparison result;

Step S235: determining whether the difference signal is not less than the threshold difference according to the comparison result, if the difference signal is not less than the threshold difference, step S240 is performed, otherwise step S290 is performed;

Step S240: determining that a touch event occurs by the first touch sensing unit SUc;

Step S290: It is determined that the first touch sensing unit SUc does not have a touch event.

In the flow 200 of the signal processing method of the touch panel, since the number of the plurality of second touch sensing units SUa1 to SUa8 adjacent to the first touch sensing unit SUc shown by the sensing determination array 100 is 8, N is equal to 8. In an embodiment, only the second touch sensing units SUa2, SUa4, SUa5, and SUa7 may be selected as the touch event determination basis of the first touch sensing unit SUc, and N is equal to 4. In another embodiment, the sensing array according to the detection of the touch event may be a 5x5 array, and N may be equal to or less than 24. Since the processing step of calculating the average value is not performed in the flow 200 of the signal processing method, the signal processing accuracy can be avoided.

FIG. 3 is a flow chart showing a second embodiment of the signal processing method based on the sensing determination array 100 shown in FIG. 1 according to the present invention. As shown in FIG. 3, the process 300 of the signal processing method of the touch panel includes the following steps:

Step S305: The first sensing signal SSc of the first touch sensing unit SUc is captured, and the second sensing signal SSa1 of the plurality of second touch sensing units SUa1 to SUa8 adjacent to the first touch sensing unit SUc is captured. SSa8;

Step S309: comparing the first sensing signal SSc with the noise threshold to generate a first pre-comparison result;

Step S310: determining whether the first sensing signal SSc is not greater than the noise threshold according to the first pre-comparison result, if the first sensing signal SSc is not greater than the noise threshold, step S390 is performed, otherwise step S314 is performed;

Step S314: comparing the first sensing signal SSc with each of the second sensing signals SSa1 SSaa8 to generate a second pre-comparison result;

Step S315: determining, according to the second pre-comparison result, whether the first sensing signal SSc is not greater than any one of the plurality of second sensing signals SSa1 to SSa8, if the first sensing signal SSc is not greater than any of the plurality of second sensing signals SSa1 to SSa8. , step S390 is performed, otherwise step S320 is performed;

Step S320: The first sensing signal SSc is amplified by N times to generate a first signal, where N is the number of the plurality of second touch sensing units SUa1 to SUa8;

Step S325: adding the plurality of second sensing signals SSa1 to SSa8 to generate a second signal;

Step S330: Subtracting the second signal from the first signal to generate a difference signal;

Step S332: Count all the second sensing signals SSa1 SSaa8 to be greater than the number of noise thresholds to generate the total number of touch points;

Step S333: comparing the total number of touch points with the critical number to generate a third comparison result;

Step S334: determining whether the total number of touch points is greater than the critical number according to the third comparison result, if the total number of touch points is greater than the critical number, step S339 is performed, otherwise step S364 is performed;

Step S339: comparing the difference signal with the first critical difference to generate a first comparison result;

Step S340: determining whether the difference signal is not less than the first threshold difference according to the first comparison result, if the difference signal is not less than the first threshold difference, step S345 is performed, otherwise step S364 is performed;

Step S345: determining that the first touch sensing unit SUc has a heavy pressing touch event;

Step S350: Filtering the false touch event caused by the heavy pressing event by the first critical difference;

Step S364: comparing the difference signal with the second critical difference to generate a second comparison result;

Step S365: determining whether the difference signal is not less than the second threshold difference according to the second comparison result, if the difference signal is not less than the second threshold difference, step S370 is performed, otherwise step S390 is performed;

Step S370: determining that a light touch touch event occurs in the first touch sensing unit SUc;

Step S390: It is determined that the first touch sensing unit SUc does not have a touch event.

In the flow 300 of the signal processing method of the touch panel, the second critical difference is smaller than the first critical difference. Similarly, since the processing steps of the average value are not performed in the process 300 of the signal processing method, the signal processing accuracy can be avoided. In addition, by determining the operation corresponding to the first threshold difference and the second threshold difference, the heavy touch event and the light touch event can be detected, and when the heavy touch event is determined, the filter is filtered. In addition to the false touch event caused by severe electric field interference in the area affected by heavy pressing, a highly reliable touch detection mechanism can be provided. Please note that during each judgment period of the touch panel, when any real touch occurs, whether the heavy press event occurs may be detected through the judgment operation corresponding to the total number of touch points and the first critical difference. And may further filter the false touch point caused by the heavy pressing according to the first critical difference value. The step of step S350 is to filter the false touch event caused by the heavy pressing event by the first threshold difference, and may include setting a heavy pressing effect centered on the first touch sensing unit SUc according to the magnitude of the first threshold difference. a region, and the light touch touch event in the affected area (ie, the difference signal of the first sensing signal SSc corresponding to the first touch sensing unit SUc is less than the first critical difference) is regarded as a false touch Filter out events and filter them out.

Fig. 4 is a view showing an operation example of the touch panel 400 based on the sensing determination array 100 of Fig. 1 in conjunction with the signal processing method shown in Fig. 3. As shown in FIG. 4, the touch panel 400 includes a plurality of sensing determination arrays 410-440. In the operation example shown in Fig. 4, the noise threshold is set to 20, the first critical difference is set to 200, the second critical difference is set to 50, and the critical number is set to 6. In the sensing determination array 410, the first sensing signal SSc (28) is greater than the noise threshold (20) and greater than each of the second sensing signals SSa1 to SSa8 (≦23), as for the total number of touch points ( 3) is less than the critical number (6), and the difference signal (66) corresponding to the first sensing signal SSc (28) is between the first critical difference (200) and the second critical difference (50) Therefore, a light touch touch event corresponding to the first touch sensing unit SUc of the sensing determination array 410 can be detected. Similarly, a light touch touch event corresponding to the first touch sensing unit SUc of the sensing determination arrays 430 and 440 can also be detected.

In the sensing determination array 420, the first sensing signal SSc (79) is greater than the noise threshold (20) and greater than each of the second sensing signals SSa1 to SSa8 (≦61), as for the total number of touch points ( 8) is greater than the critical number (6), and the difference signal (243) corresponding to the first sensing signal SSc (79) is greater than the first critical difference (200), so that the sensing judging array can be detected. a first touch touch event of the first touch sensing unit SUc of 420, and then a heavy pressing influence area 490 centered on the sensing determination array 420 according to the first critical difference value (200), and filtering out the heavy pressing influence area 490 The false touch event (light press touch event) occurs, that is, the light touch touch event corresponding to the sensing determination arrays 430 and 440 is filtered out.

In summary, in the signal processing method of the touch panel of the present invention, since there is no processing step of calculating the average value, the signal processing accuracy can be avoided. In addition, the judging operation corresponding to the total number of touch points and the two-phase different critical difference can be utilized to detect the light touch touch event and the heavy press touch event, and filter out when the heavy touch event is determined A high-reliability touch detection mechanism can be provided due to a false touch event caused by severe electric field interference in the affected area.

While the present invention has been described above by way of example, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100, 410 ~ 440. . . Inductive judgment array

200, 300. . . Process

400. . . Touch panel

490. . . Heavy press affected area

S205～S290, S305～S390. . . step

SSa1~SSa8. . . Second induction signal

SSc. . . First induction signal

SUa1~SUa8. . . Second touch sensing unit

SUc. . . First touch sensing unit

Figure 1 shows the sensing decision array used by the touch panel to detect touch events.

2 is a flow chart of a first embodiment of a signal processing method based on the sensing determination array shown in FIG. 1 according to the present invention.

FIG. 3 is a flow chart showing a second embodiment of the signal processing method based on the sensing determination array shown in FIG. 1 according to the present invention.

Fig. 4 shows an example of the operation of the touch panel based on the sensing judging array of Fig. 1 in conjunction with the signal processing method shown in Fig. 3.

200. . . Process

S205～S290. . . step

Claims (17)

A signal processing method for a touch panel, the touch panel includes a plurality of sensing judging arrays, and each sensing judging array of the plurality of sensing judging arrays includes a first touch sensing unit and a plurality of first touch sensing units In the second touch sensing unit, the signal processing method includes: magnifying the first sensing signal of the first touch sensing unit by N times to generate a first signal, where N is the second touch sensing unit The plurality of second sensing signals of the second touch sensing units are combined to generate a second signal; the second signal is subtracted from the first signal to generate a difference signal; and the difference signal is A first threshold difference is compared to generate a first comparison result; and determining, according to the first comparison result, whether the first touch sensing unit has a touch event. The signal processing method of the touch panel of claim 1, wherein the step of determining whether the first touch sensing unit generates the touch event according to the first comparison result comprises: if the difference signal is not smaller than the first The threshold difference determines that the touch event occurs in the first touch sensing unit. The signal processing method of the touch panel of claim 2, wherein determining that the first touch sensing unit generates the touch event is determining that the first touch sensing unit occurs One press touch event. The signal processing method of the touch panel of claim 3, further comprising: after determining that the first touch sensing unit generates the heavy touch touch event, setting the first touch sensing according to the first threshold difference The unit is centered to press the affected area and filter out the false touch event caused by the heavy pressing touch event in the heavy pressing affected area. The signal processing method of the touch panel of claim 4, wherein the difference signal of the first sensing signal corresponding to the first touch sensing unit of the false touch event is smaller than the first critical difference. The signal processing method of the touch panel of claim 1, wherein the step of determining whether the first touch sensing unit generates the touch event according to the first comparison result comprises: if the difference signal is not greater than the first The threshold difference determines that the touch event does not occur in the first touch sensing unit. The signal processing method of the touch panel of claim 1, wherein the step of determining whether the first touch sensing unit generates the touch event according to the first comparison result comprises: if the difference signal is not greater than the first a threshold difference, the difference signal is compared with a second threshold difference that is less than the first threshold difference to generate a second ratio Comparing the result; and determining, according to the second comparison result, whether the touch event occurs in the first touch sensing unit. The signal processing method of the touch panel of claim 7, wherein the step of determining whether the first touch sensing unit generates the touch event according to the second comparison result comprises: if the difference signal is not less than the second The threshold value is determined to be that the first touch sensing unit generates the touch event, wherein the touch event is a light touch touch event. The method for processing a touch panel according to claim 7, wherein the step of determining, according to the second comparison result, whether the first touch sensing unit generates the touch event comprises: if the difference signal is not greater than the second The threshold difference determines that the touch event does not occur in the first touch sensing unit. The signal processing method of the touch panel of claim 1, further comprising: comparing the first sensing signal with a noise threshold; and determining if the first sensing signal is not greater than the noise threshold The touch event does not occur in the first touch sensing unit. The signal processing method of the touch panel according to claim 10, wherein the first sense is The step of comparing the signal to the noise threshold is performed before the first sensing signal of the first touch sensing unit is amplified by N times to generate the first signal. The signal processing method of the touch panel of claim 1, further comprising: comparing the first sensing signal with each of the second sensing signals; and if the first sensing signal is not greater than the second sensing signals Either, it is determined that the touch event does not occur in the first touch sensing unit. The signal processing method of the touch panel of claim 12, wherein the step of comparing the first sensing signal with each of the second sensing signals is to amplify the first sensing signal of the first touch sensing unit N times to execute before the first signal is generated. The signal processing method of the touch panel of claim 1, further comprising: counting the number of the second sensing signals greater than a noise threshold to generate a total number of touch points; and the total touch The number of points is compared with a critical number to produce a third comparison result. The signal processing method of the touch panel of claim 14, wherein the step of determining whether the first touch sensing unit generates a touch event according to the first comparison result comprises: according to the first comparison result and the third The comparison result determines the first touch sensing list Whether the meta-event occurs. The signal processing method of the touch panel according to claim 14, wherein the step of comparing the total number of touch points with the critical number to generate the third comparison result is performed by the difference signal and the A threshold difference is compared prior to generating the first comparison result. The signal processing method of the touch panel of claim 14, wherein the step of comparing the total number of touch points with the critical number to generate the third comparison result is subtracting the first signal from the first signal The second signal is executed after the difference signal is generated.